This is a common question. Type of sensor (Z-Wave, Zigbee, WiFi, LoRa) depends on your enviroment and the mailbox distance from your hub or repeater/relay device.
I've recently transitioned from using a contact sensor, to a motion sensor. Both work well, but in my particular situation, a motion sensor is better for me and the layout of the box (community mailbox in my case).
For distance, nothing competes with LoRa, not even Z-Wave Long Range. Of course LoRa is not a directly supported protocol by Hubitat, so I used a Device to Device connection between a Yolink LoRa motion sensor, and a Yolink LoRa Relay. When the relay contacts close, it signals a Zigbee button push, but you could use almost any Hubitat compatible input device for this, such as a Z-Wave or Zigbee contact sensor.
Most with mailboxes at their homes probably won't need the range of a Yolink LoRa sensor, but for those that have range issues, the LoRa contact sensor, motion sensor, or tilt sensor cannot be beat, and their D2D connection is completely local. One caviat to using the Yolink motion sensor for this purpose is that it only reports motion active. So when it's joined via D2D with their relay, it can either turn the relay ON or it can turn it OFF. It cannot do both. The answer is to configure their relay for "Pulse Mode", but to do that you have to have their hub. The contact sensor and tilt sensor do not have this requirement since they can be joined to turn the relay ON in one state, and turn it OFF in the other state (i.e. contacted/not contacted or tilted/not tilted.
For those needing the range of LoRa, and a rural type mailbox where the door tips out, the Yolink Garage Door kit has just what you need. Simply connect a Z-Wave or Zigbee button or contact sensor to the "sensor" contacts on the Yolink garage door relay. The Yolink relay included with the garage door kit is almost the same as the regular Yolink Relay, but it only has low voltage contacts, and is limited to a 5v DC supply voltage.
